1. Field of the Invention
This invention relates to process control of manufacturing of integrated circuit (IC) chips and more particularly to dispatching of work to the various processing stages in a fabrication plant.
2. Description of Related Art
The traditional dispatching rules (e.g. First in First Out (FIFO), Earliest Due Date (EDD), Critical Ratio (CR), etc.) cannot meet the requirements of Integrated Circuit (IC) manufacturing due to the complexity of the fabrication process (above 300 process steps) and the limited resource in IC plants. Inappropriate dispatching rules cause higher cycle times and reduce machine utilization rates, resulting in decreased customer satisfaction and reduced flexibility in product life cycle. The net result is increased capital investment cost.